Saponification of cellulose ester textile materials



Patented Mar. 12, 1940 V UNITED STATES PATENT OFFICE SAPONIFICATION OFCELLULOSE ESTER- TEXT1LE MATERIALS Henry Dreyfus, London, England NoDrawing. Application May 5, 1937, Serial No. 140,896. In Great BritainJune 3, 1936 3 Claims. (01. 8130) This inventionrelates to themanufacture of phuric thio-sulphuric and phosphoric acids, exl'naterialscomprising filaments, fibres, yarns, eluding tri-sodium andtri-potassium phosphates. ribbons, films and the like containingcellulose Preferably the 'saponifying medium is applied acetate or otherorganic esters of cellulose, and is in a bath treatment, and when anaqueous soluparticularly concerned with the saponificatlon of tion ofguanidine is employed a concentration of 5 such materials. 3-10 or 20%of guanidine is suitable. A tempera- According to the present inventionsuch mateture between 30 and 60 C., or even higher, or rials aresaponified by treatment with guanidine. less than 30 C., for instance 15to 20 C., may

Thus ;by employing an aqueous solution of be employed. The saponifyingmedium may or 10 guanidine as the saponiiying agent, a rapid may not beunder pressure. The materials may 10 saponiflcation may be carried outwithout delebe passed through a bath containing the saponiteriouslyaffecting the serimetric properties of y n a e t, t a at depending p t e0 the material. The treatment may, in fact, concentration of theguanidine or guanidine derivasiderably increase the tenacity and/or theextive present, the temperature of the bath, and the tensibility of thematerials. amount of saponification desired. Yarns of cel- 15 Accordingto a modification of the invention lulose acetate or other organicesters of cellulose alkyl and aralkyl derivatives of guanidine, such m ye P e n in sly thro h the ba h, for example as methyl guanidine,dimethyl preferably in "warp formation, i. e., alarge numguanidine, andsymmetrical dibenzyl guanidine ber of ends are drawn through the bath insubmay be employed instead of. guanidine itself. It stantially parallelrelationship to each other and 20 is to be understood that the term aguanidine in he S me p es yarns in p fermecompound" employed in theclaims includes such ion may be rawn by means f ui le o derivatives aswell as guanidine itself. r0118. 0 e b s, P t y 0 completely Theguanidine or guanidine derivative may be mersed in the bath andextending across the applied to the materials to be treated in any suit-Whol Wa p. hr h a r n n through able manner. Preferably it is applied ina met e bath, nd e through a u h eed or 25 dium containing hydroxygroups, and particularly reeds to suitable collecting means situated'outgood results are obtained by applying it in side the bath.Preferably the yarns are washed aqueous'solution. The guanidine orguanidine n dried ef r being Wound,

derivative may, however, be applied in alcoholic The yarns y, however, ea ed in a k solution or in solution in a mixture of water and form byuspe e an o rods which alcohol. The alcohol present may be, for exarecaused to travel from one end of the bath to ample, methyl, ethyl,propyl or butyl al h l, the other but at the same time to revolve so asethylene glycol or its monomethly or monoethyl to immerse each portionof the hank in turn to 5 ether, glycerol, benzyl alcohol, cyclohexanolor dith sa e dep Yarns in the form o hanks, acetone alcohol. Otherhydroxy solvents, swellk s r other suitable packages, for instance ingagents or latent solvents for the organic ester w u on feraminous pp s,m y be oof cellulose may be present. The saponifying dueed nto a b th Cn a n g the aponifying medium may contain a non-hydroxy solvent, agentand allowed to remain in contact therewith w swelling agent or latent 1vnt, for example until the'desired degree of saponiflcation is ef- 0cyclohexanone, acetone, methyl-ethyl-ketone, difeeted; e sapenifying edum may be ciroxane, methylene ethylene ether, ethylidine culated throughthe yarn, for instance it maybe ethylene ether, or the dimethyl' etherof ethylene pump backwards an forwards u h yarn glycol, wound on aforaminous package carrier.

The saponifyingmedium may contain a sub- S indicated above, thematerials may be stance which diminishes its swelling action on thesepehified in fabric m, and a convenient organic ester of cellulose, asdescribed in U. S. manner of ec g such sapo fiea n s by application S.No. 81,268 filed May 22, 1936, Pat- Passing e ab c c t u usly thro h abath ent No. 2,091,972. Examples of such substances e ntaining the sapoyi medium, for example are sugars and water-soluble salts of organic inapparatus the. p of the Winh yein acids, particularly non-soap formingaliphatic a' acids, e. g., the sodium, potassium and ammonium Thematerials undergoing saponification may salts of acetic,tartaric,'citric and lactic acids, be maintained under considerableapplied tenend of poly-basic inorganic acids, e. g., the sosion, or maybe under little or no tension, so that dium, potassiumand ammonium saltsof sulcontraction may take place. In the case of travelling materialsthe rate of travel may be made to decrease along their path with aviewto minimizing the tension.

The materials prior to saponification may be pre-treated in order tofacilitate penetration of the saponifying medium. Thus the materials maybe pre-treated with water or an aqueous cellulose acetate.

they may have been formed inorganic softening agent, or

The filaments and the like treated may be made by wet or dry spinningprocesses. The cellulose acetate or other organic esters of celluloseforming the basis of the materials may be of high, medium or lowviscosity. Thus in the case'of cellulose acetate, the viscosity may bebetween 10 or less and 25 or 30, or may be higher, for example 30 up to100, 200 or more, these figures being those obtained by comparing the:viscosity of a 6% solution of the cellulose acetate in acetone at 25 0.,with the viscosity of glycerine at the same temperature taken as astandard of 100.

The materials treated may have been submitted to a stretching operation,for instance process in which they are stretchedconsiderably, or theymay have been stretched after their formation under the influence of anorganic or of steam or hot water. Theproducts of such processes are ofhigh tenacity, e. g., 2.5-3, 4 or more grams per denier, and affordparticularly valuable products when treated according to the presentinvention.

The materials stretched or unstretched may have been subjected toshrinkage, for instance by treatment with methylene chloride-benzenemixture.

By means of the process of the invention, the

materials may be saponified to any desired extent, for instance to suchan extent that the materials acquire an 'afllnity for cotton dyestuffsbut do not lose their affinity for cellulose ester dyestuffs, forexample the dispersed insoluble dyes, or to such an extent that theaffinity for by a wet spinning cellulose ester dyestuffs is destroyed.The mate- I rials may be saponified tov raise the safe ironing point.The degree of saponification efiected may be suflicient to reduce .theacidyl content of the ester by 10% or less, or the loss of acidyl may beconsiderably higher, for instance there may be a loss of 20 to 30 or 40%or even more of the acidyl content. The materials may even be saponifiedcompletely.

The following example illustrates the invention:

Cellulose acetate artificial silk of high tenacity is immersed in a 4-6%aqueous solution of guanidine at 40-50 C. until completely saponified..It is then removed, washed and dried.

In a similar way alkyl or aralkyl substituted guanidines can be used, e.g., monoor di-methyl guanidine or symmetrical dibenzyl guanidine.

Colouration of the-materials, for instance with cotton dyestufis orcellulose ester dyestuffs according to the degree of saponiflcation, maybe effected continuously with saponiflcation, and dyestuffs, forinstance dispersed'insoluble dyes,

-may be applied in the saponifying medium itself.

Having described my invention what I desire to secure by Letters Patentis:

1. Process for the production of improved artificial materials, whichcomprises immersing materials comprising filaments, fibers, yarns,ribbons and the like having a basis of a ripened organic ester ofcellulose and tenacity of at least 2.5 grams per denier in a 3 to 20%aqueous solution of guanidine until the acidyl content of the materialsis reduced to at least 20% of the original acidyl content of thematerials.

2. Process for the production of' improved artificial materials, whichcomprises immersing materials comprising filaments, fibers, yarns,ribbons and the like having a basis of acetonesoluble cellulose acetateand tenacity of at least 2.5 grams per denier in a 3 to 20% aqueoussolution of guanidine until the acidyl content of the materials isreduced to at least 20% of the original acidyl content of the materials.v I

3. Process for the production of improved artificial materials, whichcomprises immersing materials comprising filaments, fibers, yarns,ribbons and the like having a basis of acetonesoluble cellulose acetateand tenacity of at least 2.5 grams per denier in a 3 to 20% aqueoussolution of guanidine until the materials are substantially completelysaponifled.

, HENRY DREYFUS.

